Recording device



June 3, 1952 A. KILLE RECORDING DEVICE 4 Sheets-Sheet 1 Filed Sept. 5, 1947 ATTORNEY June 3, 1952 l.. A. KILLE 2,599,392

RECORDING DEVICE Filed Sept. 5, 1947 4 Sheets-Sheet 2 June 3, 1952 l.. A. KILLE RECORDING DEVICE Filed Sept. 5, 1947 4 Sheets-Sheet 3 L. A. KILLE June 3, 1952 ed Sept. 5, 1947 y /NVE/vTo/e L. A. K/LLE Patented `lune 3, 1952 UNITED STATES PATENT OFFICE RECORDING DEVICE Lindley .Kille,-Morristown, N. J., assigner to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application September 5, 1947, Serial No. 772,301

. 6 Claims. l

This invention relates to recording devices and particularly to means for insuring thel probable correctness of a record in the process of its production.

The guiding principle of the present invention is to be found in the laws of probability and may be stated simply as, whereas the probability that even a trained operator may occasionally commit an error is reasonably certain, the probability that two trained operators will simultaneously commit the same error is remote.

The object of the invention is to provide means which will insure the probable correct formation of a record and which will automatically fail to record an error. Another, and more specic object is to insure the preparation of a perforated tape when and only when a correct code is offered for recording.

In accordance with this invention, two .operators keyboards are provided which are combined with a matching circuit and a single tape perforator. Two operators simultaneously write up the same information, the output of one keyboard is matched against the output of the other and if and only if the match is perfect, the information is recorded by the tape perforator.

Each keyboard has a bank of keys each of which when operated will remain in its operated position until automatically released. The releasing means is under control of the matching means and automatically responds when the two operators simultaneously operate like keys, so as to prepare the key sets for the next operation,

whereby a pair of skilled operators may record prearranged information at a satisfactory speed.

Each key hereinabove set forth is arranged to transmit a code consisting of a fixed plurality of elements, In addition there is provided at each key set a plurality of code element keys vwhereby the operators may create codes for transmission. By this means, mutilated or erroneous codes may be produced and will be transmitted and recorded when and if the two operators simultaneously form the same code, either perfect or mutilated. Thus codes mutilated by operator agreement may be produced.

Another feature of the present invention is a means for repeatedly recording the same code without having to key it repeatedly. In accordance with this feature the key releasing means may be disabled so that the keys operated will not be automatically released when a match has been attained and the code recorded.

Another feature is a means to release the control operators key set from the teamwork control whereby it may be used as a single control.

The drawings consist of four sheets having six gures as follows:

Figs. 1, 2, 3 and 4 arranged as shown in Fig. 6 form a complete schematic circuit diagram of the elements of the present invention and in which:

Fig. 1 shows the keys and relays for the A digit at both the control operators position and the assistant operators position;

Fig. 2 shows in full the keys and relays for the digit B of the two operators positions and indicates similar arrangements for the C. D, l.E and F digits;

Fig. 3 shows the relay control means;

Fig. 4 s ows the cut-in relays and indicates the perfor tor;

Fig. 5 exemplifies a short piece of perforated tape; and

Fig. 6 shows the arrangement of Figs. l, 2, 3 and 4 as hereinabove set forth.

The device of the present invention provides means for the fabrication of test tapes used in an automatic message accounting system. These test tapes are ones which are made by hand in order to test the operation of the various units of the automatic message accounting system. The device consists of two separate key sets mounted on a common table which also mounts necessary control keys, lamps and relays and is associated with a conventional perforator cabinet.

In the perforation of automatic message accounting tape according to one type of coded information which may be used, twenty-eight possible code hole positions are provided for each line and each line consists of six digits arbitrarily designated A, B', C, D, E and F. In all digits B to F, inclusive, ve code hole positions for each digit are provided and any one of the ten digits can be perforated according to a two-out-of-ve additive code in which the code holes for each digit are designated 0, 1, 2, 4 and 7 and in which:

5:4 and 1 y A .6:4 and 2 7:7 and 0 8:7 and 1 9:7 and 2 0:4 and 7 1:1 and 0 2:2 and 0 3:2 and l 4:4 and 0 2:2 3:0, 1 and 2v In Fig. a short piece of tape is exemplified and broken lines have been drawn lengthwise along this tape, in order to illustrate the three positions for the A digit and the ve positions for each of the remaining digits. In the top line a code for 081010 is shown by way of example. This shows a hole punched in the 0 position of the Adigit, two holes punched in the 1 and '7 positions of the B digit, two holes punched in the 0 and 1 positions of the C digit, two holes punched in the 4 and 7 positions of the D digit, two holes punched in the 0 and 1 positions of the E digit and two holes punched in the 4 and 7 positions of the F digit. This particular code 081010 isknown.

cording magnets for the purpose of producing a kta'pe'which might Vlook like that illustrated in Fig. 5. The present invention isin no way limited to any particular typeof code or to any particular number of code elements on the recording medium and furthermore is not limited to any particular type of recording medium, since it will be obvious to those-skilled in the art that the recording magnets shown in Fig. 4 could be used to produce rarecord in media other than a perforated tape.

In order to insure probable accuracy two operators lare employed. These operators work from duplicate typed lists of entry numbers. The tape to beperforated may be leither a normal tape or an error tape, that is, a mutilated code '.tape. A normal tape as used in this description is :one which icontains two andtwo only perforations in theB, C, D, E and vF-digits and one and Aone onlyorah three perforations in the A digit.

yAn error'tape is 'one containing too few or too many perforations in one or more digits.

Each -operators key set contains fty-four regular V.push-.button type .mechanically locking `and electrically releasing key buttons. These :keys arefnumered 0 to 9 for the B, C, D, E and F digits and 0 to 3 for the A digit. These key buttons are'usedfor producingnormal digits .containing twof and two only perforations in the B Lto-F digits and one and one :'only or all three perffo'rations in the A digits. 4also-'contains'thirty-four error lever type 'locking keys fused only for producing defective digits.

Each operators key set Twenty-eight of these errorsv keys are designated 0,.1,'2, 4 and 7 for the .B to F 'digits and 0, 1

and- 2-for'the A digit. Each of these keys -when `operatedrrcauses the perforation of onefhole-in -itslparticular .digit as indicated by the designations 0, 1, 2, 4 and '7. The remaining six error keys are designated NA, NB, NC, ND, NE and NF. Each of' these Ykeys when operated performs no function other than to provide a positive operation for the'digit and to insure the release of the regular -keys for its respective digit. The defective line when perforated as subsequently described will,.however, contain a blank space for `the digit in which the .N key .only has 'been operated.

`In 'the perforation of normaltapesthe six digits of each entry line are keyed up on the operator key sets by the operators line by line using the mechanically locking regular push-button type keys. Whenall'six digits of any particular 4the slower of the two operators.

line as keyed by the two operators agree, the line is automatically perforated and perforate control (PC) lamps in front of the two operators ash to indicate perforation and the operated keys of both operators key sets are automatically restored. The two operators then key the next ,line and this 'process is continuedso long as both operators key matching-lines, the speed of operation being limited only by the accurate speed of In case one operator keys inaccurately, perforation will not occur, the perforate control (PC) lamps will not flash, and the operators keys will not be restored. The operators will then determine which keyf has been-wrongly operated. The inaccuracy may be corrected by operating the correct key whereupon perforation and the automatic restoration of the operators keys will occur and the normal process of automatic perforation will continue as before until a subsequent mistake is made by either operator.

To produce error tapes it is necessary to operate the manual control key before keying up the line in which the defective digit is desired. The operation of= the manualcontrol key enables the error lever type locking keys by connecting .perforation any regular keyswhich are voperated will not automatically restore. This manual control feature is necessary in perforating error lines since the use of-locking keys'forregistering the individual 'holes of the rdefective digits 'might otherwise cause prematurerperforations due to accidentali matches during keying. The manual control key is also operatedwfor making repetitive linessuchas the splice pattern hereinbefore described. In `this case therepeat perforation key w-illusually be operated in .place of the manual perforation key. The 'circuit will then cause the perforation of successive lines of any digits set -up on the operators keys 'at a speed of about' three per'second so longsas' the repeat perforation keyremains operated.

AWithvthe Isingle control .key .I0 operated the circuit will `perform any ofthe -operations mentioned yabove `-except that'the 'operation of the control operators keys onlyiis required. In this ease' there is, of course, no-check onthe accuracy of the operators keying.

To prepare this circuit for operationpa suitable perforator'fis plugged intolthe jackof this circuit Vand apower switch r(not'shown) isfoperated to activate thevdevice. The -Aperforator -is herein yindicated in Fight inthe broken Aline rectangle I in -which-twenty-ninefmagnets connectedlto plugs are-shown. IThe top-magnetzisrthe'tape advance' magnet and-the other twenty-eight 4magnets are those which 'causethe perforations in the'tWenty-eight positions 'offthe' tape. VThe-sep- "arate rvbattery supplies for v`these magnets are -in parallel l'an'dr operatesimultaneously i-as the `equivalent fo'f Ava. lsirif'gile--1riulti==contaatfrelay. A

rectangle shown connected to the conductor leading to the operated windings of the CI, C2 and C3 relays and marked CP represents a conventional contact protection network provided to minimize the sparking at the contacts of the relays which operate this circuit.

As each line is written up by the two operators on the regular keys the operation of one key in each digit by each operator operates two out of ve register relays in the B, C, D, E and F digits and one out of three or all three register relays in the A digit. We will assume by way of example that both operators have written the number 081010 on their keys. Therefore, in Fig. 1 the key designated A in the regular column of the control operators keys and the key designated A0 in the regular column of the assistant operators keys have been operated. Likewise, in the B position the key designated 8 in the original column of the control operators keys and the key designated 8 in the regular column of the assistant operators keys have been operated. Similar operations in the other digits will be assumed. Thereupon, a circuit will be established yfrom ground, armature 2 and front contact of front contact of the CBI relay and in parallel therewith armature I and front contact of the CB1 relay, thence through similar circuits over conductor in each of the C, D, E' and F digits back to armature 2 and front contact of the CAa'l relay, front contact and armature of the AAU relay and thence in series through back contacts and armatures of the AAI, the CAI the CA2 and the AA2 relays to conductor 3 leading to a similar circuit in the B digit position where it may be traced through armature 2 and back contact of the CBI! relay, back contact and armature of AB!) relay, armature and front contact of the ABI relay, front contact and armature 2 of the CBI relay, armatures and back contacts of relays CB2, ABZ, ABA, CBB, armatures and front contacts of relays CB1 and AB1 to conductor 4 which may now be traced in series through similar circuits indicated in the C, D, E and F digits to the windings of relays CI, C2 and C3 in parallel and thence to battery. It will be noted that this circuit will be closed to cause the operation of the cut-in relays CI, C2 and C3 only if some one relay such as CAI] in each of the digits has been operated and only if when such a relay as CAI) has been operated its companion AA is also operated. In each position the relays such as CAD and AAG are in pairs and both relays of a pair must be operated, for one breaks the conl tinuity of the circuit and the other repairs this break.

` bered I, the zero perforator magnet 1 for the A f digit to battery. For each of the C relays such as C'AU or CBI a corresponding perforator magnet is operated.

Relay CI operated also connects ground to operate the perforator advance magnet in a circuit ywhich may be traced from ground, front contact and upper outermost armature of relay CI, back contact and armature 2 of PAMR relay (perforator advance magnet relay), perforator jack spring 43, perforator advance magnet 2, perforator jack spring 32 through a limiting network to battery. A circuit is also established from ground, front contact and armature 4 of the PC relay, upperV next-to-outermost armature and front contact of the CI relaywinding ofthe MR relay'tobattery and ground. Relay MR operated connects an additional holding ground to the perforator advance magnetA and operates relay PAMR. Relay PAMR operated disconnects the original operating ground from the perforator advance magnet and releases the PC relay. Relay PC released, (a) lights the PC lamps to indicate to each of the operators that the perforation of the line has occurred, (b) releases relays CI, C2 and C3 by breaking their original circuit,r(c) operates relays KR and KRL, and (d) Vreleases relay MR. The circuit for` relays KR andKRL may be traced from ground, armature. 3 and back contact of the PCH relay, armature 2 and hack contact of the MC relayv to the windings of relays KR and KRLin parallel to ground. Y The circuit for relay MR is broken at the front contact of armature 4 ofthe PC relay.

Relay KR operated connects ground to -operate all key release magnets. By way of example, the

y key release magnet 8 controlling the regular keys for the A digit on the control operators key set is yoperated from ground, armature I and front contact of the KR relay, the winding of the KRM magnet (lower left of Fig. 2) to battery and ground. Other key release magnets are operated in a similar manner. .g

The operation of the key release magnets releases all operated keys which in turn release all operated register relays. Relay KRL operated locks itself tov conductor 9 so that it is not until every operated regular key releases that the relay KRL willrelease. This will insure that all keys have been released before the keying of the next digit. If for any reason any one of the operated keys should fail to release when the KR vthe full operation of all perforator punch magnets. Relay MR released releases the perforator advance magnet causing the perforator to step. Relay MR is made slow to release to insure that all perforator punch rods have been withdrawn before the perforator step occurs. Relayl MR released also releases relay PAMR. Relay PAMR released reoperates relay PC and partially recloses the circuit for operating the perforator advance magnet. Relay PC reoperated connects ground to the register up-check chain preparatory to the next perforation and extinguishes the PC lamps. Relay PAMR is slow to release to insure against the reoperation of the perforator punch magnets before the stepping of theperforator has been completed which mightv otherwise occur in the case of repeated perforations as will be described hereinafter. When the digits of each subsequent line are correctly written up by both operators. the operations just described" are repeated for each line. Y

Manual operation "Whenf a line containing defective v'digits is tobe l perforated rorwhen repeated'vperforation of a `Vparticular line isrequired, fthe locking -manual Ycontrolkey is operated before thekeying ofthe 'line,\ thereby operating relay MC. v`RelayMCoperated (a) venables theverrorkeys of all' digits by connecting vground tov onevof the movable contacts fof each key.' (b) opens the circuits'ofrthe andKRL relaysto prevent the automatic restoring yof any regular keys upon perforation, (cloperates relay SR, (d) connects ground -to"en 3able the-manual perforation and the repeat per- 'foration keys, (e) modies the fundamental fcheckcircuit for the operation of the Cl, C2` and C3 cut-'in relays by disconnecting the upcheck chaina'nd placing the control of the Cl,"C2'and G3'relaysun'der control' of the match'check chain andthe-contacts of 'the' LOand MP relays, and (j) @partially closes a rcircuit for the operation of -the LO- relay whenv relay PC releases after"per foration as subsequently described. It`may be noted that upon theoperation of the MC'relay 4a-circuitl is established'which is closed by either ythe -manual v perforation or the repeat perfora- -`tion keys from ground, front Ycontact and l arma- 'turef'l-ofithe MC relayfthe contactsof 'either them'anual perforation key or' the repeat per- "ffration key,"arma`t'ure5 and front contact of the AP'Crelay, armature! arid back contact Y' ofthe yLO relay-tot'hewinding -of the lVlPrelay. With relax/"MP Voperated the circuit -for the'CLCZ and C3 relays extends from ground, armature 2 and frontcontact fof "the 1` PC i relay,` 'armature 2 and 'frontllcontaet of A fthe-2MP lrelay to the check cir- Tc'iiits'heretoforedescribed and-Which heretofore `4camel.from 'armatureS'fof theiMC relay.

To' perforate v'atline containing defective digits "the"."defective digits-are Written up on the error operated. "TheN keyjperforms no function other y than 'to'providea positive operation' bythe op- A"eratorior that digit and toinsurathe release ofany 'regular 'key whichmay have been incorfrectlyoperated for thatdigit.

The non-defective digits may bewrittenupas g i'usual on the regulan keys. v.ln 'this' c'ase,-perora tion Adoes'fnot Vloc'cur automatically when fboth koperators have 'written iup 'the 'complete :line but lZ-a'waitsthe .operation 'of the manualfperforation ""fk'e'y. The' operation of themanual'p'erforation key-"operatesthe MP relay as described and if the registrations 'for-the line -as -Writteirbythe operv-ators agree-the operationrofthe MPl relay operatesthe`CI,-.C2 yand-C3 relays inparallel, these `relays:functioning as'before vto perforate the line 'from the contacts of the operated register relays. Relayy MP also locksfunder Vcontrol of relay MPI ini'ts normal 4posii'liri.and 'th'en operates the relay The'operation of thislatter relay removed 'the'locking circuit of 'relayMP'aft'er' asiight time interval. ThislockingV arrangement for relay MP `is"'pr'o'vided in order' Ato-'insure' the `operation of 4`relaysCl, C2" and C'Sad` the completion of the perforations in' casev of afVeryl/"shbrtoperation of the manual perforation key. *Ifitherfoperatorj `cut-in relays to startanew cycle.

continues so long as the repeatl key is held-operated causing the same .line to beperforated re- :fpeatedly =at a Yspeedl of approximately-three per has xkeyed incorrectly the C i C2 -andf C3-"rela'ys will not operate. The incorrect registrations'lmay be corrected by the operation of -the prope'rk'ey setke'yseand the operationof the manual? perforation key then causes the--operationfoftheL cute-in relays tolperforate the .line.

Relay CI operated valso operates the fpe'rforator advance magnet Yas hereinbefore describedand operates the relayMR. Relay' MR operated-connects an additional 'holding ground lfto lthe Lperforate advance "magnet and operates 1 'relay PAMRlas` before described. Relay PAMR-Eoperated Adisconnects theoriginal operating ground operates the LO relay, and(e) releases--the'-MP relay. -Thecircuit for the LO relaymay'be traced from ground, armature! and backlcontaotof -the PCv relay, 'normally closed contact of -the-y repeat perforation key, armature 6 and -f-ront conta'ct-'of *the MC relay to the winding of the-LO relay.

Relay ALO operated locks vunder control Joff'the manual perforation key if this key is-'s'till Y'oper- 'ated and opens the circuit `to the MP relay. VlrAs long as the manual perforation key isheld operated, relay LO will -be locked operated' thus preventing any further perforations until -the manual perforation keyy is 'released land v-reoperated. This assures only Ione perforationfor each 4operation'of the manual perforation key. fRelay MR released releases the perforat'or advance magnet causing the perforator to Ystep -andd'eleases relay PAMR. RelayPAli/l'l, -released'reoperates the PC relay. The PC 'relay reopei'a'ted extinguishes the PCv lamps and releases'-the-'LO relay provided the manual perforation keyl has lbeen released. In case'additional lines containing 'defective digits areA to'be perforated the manual control key must be left operated'and subsequent lines 4perforated by'correcting' -the settings of'the'operatorskey sets vas required- -for each line'and operating the manual perforation key to lperforate the lines'as :just described.

Perforationlof identical liaes -If a 'definite' number of identical" lines'f are to be perforated whether or not these lines "contain -defective digits thismay be done-as just 'hereinbefore described, operating the manual perforation key once fcreach line to be perforatedwithvout any intervening corrections lin the 'settings' of thefoperatorskeys. If, however, an approximate number of videntical lines is requiredas inn the case'of the splice pattern, 'this can-fbey accomplished more conveniently by operating -and holding the repeatperforationkey insteadrof the manual, perforation key. The -operationv of the repeat perforation .key operatesthe MP-relay which functions asfabove described. The'operation of the repeat perforation key, howevewopens the cmeratingcircuit for the LO relay. The-circuit then functions asabove -described to.A perforate the rst line =exceptthat' relay LO--does not function vandthe-operation of relayMP iupon the reop'eration of relay PC at Vthe'fend of the rst operation cycle immediately operates .-the This 'process SeCOnd.

each said key in operated position after a manual operation thereof, common key releasing means in each said key set operable for simultaneously releasing all operated keys of each said-set, electrical networks controlledby said key sets for transmitting keyed vinformation in code, a recorder having a plurality of recording magnets, connector means operable for interconnecting the said electrical networks of said control operators key set and said recording magnets to operate said magnets, a code matching circuit responsive to said electrical networks for operating said connector means responsive to a match of information simultaneously keyed at said two operators key sets, and meanscontrolled by said connector means for operating said key releasing means.

2.` A device consisting of a control operators key set, an assistant operators key set, each" said key set having a bank of keys, means for holding each said key in operated position after a manual operation thereof, common key releasing means in each said key set operable for simultaneously releasing all operated keys of each said set, electrical networks controlled by said key sets for transmitting keyed information in code, a recorder having a plurality of recording magnets, connector means operable for interconnecting the said electrical networks of said control operators key set and said recording magnets to operate said magnets, a code matching circuit responsive to said electrical networks for operating said connector means responsive to a match of information simultaneously keyed at said two operators key sets, means controlled by said connector means for operating said key releasing means, key means at said control operators set for disabling the said control of said key releasing means by said connector means, and a self-interrupting circuit controlled by said last key means for periodically and automatically disabling the said connection from said code matching circuit to said connector means whereby said device will operate repeatedly to record the same information a plurality of times.

3. A device consisting of a control operators key set, an assistant operators key set, each said key set having a bank of keys, means for holding each said key in operated position after a manual operation thereof, common key releasing means in each said key set operable for simultaneously releasing all operated keys of each said set, each said key set having keys for representing codes and other keys for representing code elements whereby either perfect codes or mutilated codes may be keyed, electrical networks controlled by said key sets for transmitting perfect codes or mutilated codes, a recorder having a plurality of recording magnets representing the elements of the said codes which may be transmitted, connector means operable for interconnecting the said electrical networks of said control operators key set and said recording magnets to operate said magnets, a code element matching circuit responsive to said electrical networks for operating said connector means responsive to a match of information simultaneously keyed at said two operators key sets, and means controlled by said connector means for operating said key releasing means.

4. A device consisting of a control operators key set, an assistant operators key set, each said v key set having a bank of keys, means for hold.- ing each said key in operated position after a manual operation thereof, common key releasing means in each said key set operable for simultaneously releasing all operated keys of each said set, each said key set having keys for representing codes, a plurality of relays operated by said keys, each said relay representing a code element, a matching circuit consisting of pairs of relays for controlling a series circuit, each said lpairl of relays consisting of a .code element relay operated by said control operators key set and a corresponding code element relay operated by said assistant operators key set, a portion of said series circuit being'normally closed through back contacts of the said relays of a pair and 'alternatively closed through front contacts of the said relays of the said pair, a recorder having a plurality of recording magnets equal'in number and corresponding to the said code element relays operated by said control operators keys, connector means operable for interconnecting said recording magnets and said code element relays to' operate each recording magnet responsive to the operation of its corresponding code elementrelay, an up-check circuit operated by the said code element relays operated by said control operators keys, said up-check circuit being in series with said series circuit and said connector means whereby said connector means responds to the closure of said up-check circuit and said series circuit and means responsive to the operation of said connector means for operating said key releasing means.

5. A device consisting of a control operators key set, an assistant operators key set, each said key set having a bank of keys, means for holding each said key in operated position after a manual operation thereof, common key releasing means in each said key set operable for simultaneously releasing all operated keys of each said set, each said key set having keys for representing codes, a plurality of relays operated by said keys, each said relay representing a code element, said relays being in a plurality of groups each said group representing a code place, a matching circuit consisting of pairs of relays for controlling a series circuit, each said pair of relays consisting of a code element relay operated by said control operators key set and a corresponding code element relay operated by said assistant operators key set, a portion of said series circuit being normally closed through back contacts of the said relays of a pair and alternatively closed through front contacts of the said relays of the said pair, a recorder havingra plurality of recording magnets equal in number and corresponding to the said code element relays operated by said control operators keys, connector means operable for interconnecting said recording magnets and said code element relays to operate each recording magnet responsive to the operation of its corresponding code element relay, an up-check circuit closed through a front contact of at least one of said relays in each of said code place groups, said up-check circuit being in series with said series circuit and said connector means whereby said connector means responds to the closure of said up-check circuit and said series circuit and means responsive to the operation of said connector means for operating said key releasing means.

6. A device consisting of a control operators key set, an assistant operators key set,each said key sethaving .a bankr ofskeys; K means aforrholdingzeach Vsaidikey y inxoperatedf position'. after: a;a

manual. operation thereof common keyr release ingcmeans v inv eachi` Asaid. V-.key/settoperable fora si,;

said:set,. each'saidr key :set havingakeys 'for' 'reperesentingLcodes,` a..plurality of-.relays;operated '.by'-,-

said keys,each saidA relay representingml codefel'ea-A ment;` saidi relays 1beingsin .-a pluralityl of-L' groups each u said groupz'representing.: a.. codea=p1ace,.,as

matchingAv :circuit 'consistingmof '.pairs; oi'frelayssfor'f` controllingI .a series; circuit, each saidfrpaim of frelaysLconsisting of atlcodeY elementrelaysoperated" byi said.V controll operator-s key' set *and/1 a corres l spondingcode element relay-1 operated byssaidai:

assistant operatorslzey set; a :portionfiof Vsaidse^- ries circuit beingfinormally'l closed: ;throughrbacki. contacts of.` the` said: relays of Ia' pair:.andalterna.;4

tively closed'sthrough .frontzcontactsr of the.-said I.

relays. of-Lthe said- .pair a;recorderrhavinga'a plus;V

rality' of ,1'ecording;magnets.. equal. in' numberzand".

corresponding: the: said -codel elemeninl relz'tys.n` operated; by. said' contro-L Y* operatorss; keys, cons'- nector meanssoperablee :for interconnecting: 'said recording magnets: and said. :code: element Lrelays.; 255 2072392 to:A operate: each.'` recording; magnet r responsive(to.`

the operation of its correspondingfcodeelement relay; an up-check circuit=closedfthroughta .front contact of .at "least r one 1of saidrelays 4each -of said .code fplacefgroups; said '.:upfcheckfcircuit beingtirr. serieswthsaid ,series circuit andsaid con@ nectormeans'wherebysaid connector meansfrey sponds .totheclosurezoi saiduprcheckcrcuit andsaidwseriesr'crcuit, ,at normallyy energizedi control relayfhaving: means when v energized-to. complete said circuitrfor fsaid connecting'xmeans :and: havingf meansfwhen 'released'.to :operate said keyg re. leasing fmeanr` and-,.means-g-.controlled hither-'om eration: of said connector-@means for:releasing:said

control relay.

LINDLEY, A. KILLE@ REFERENCES CITED f The r`-iollowing references are ot record/in "the lelof this-patent: 

